1. Field of the Invention
The present invention relates to an electrocromic rearview mirror used for an outer mirror for an automobile and improved in a water proof ability.
2. Description of the Relevant Art
It is known that the electrocromic mirror (EC mirror) is used for an anti-glare rearview mirror for the automobile in which a transparent type electrocromic device is used for automatically varying from a high reflective condition (DAY condition) to a low reflective condition (NIGHT condition).
In the EC mirror, normally a front reflecting surface of the mirror is covered(laminated) by the electrocromic device (ECD) which has a characteristic to act a reversible reaction in accordance with an applied electric current polarity so as to become a coloring condition or a bleaching condition and the reflectivity is controlled by varying the coloring level of ECD, thereby the anti-glare effect is generated against the backward vehicle head light during a night time running.
In order to obtain the effect as described above, the EC mirror is controlled so that the backward injecting light level is detected to increase the coloring level against the bright backward light (to level down the reflectivity) and to decrease the coloring level against the dark backward light (to level up the reflectivity).
While, as shown by FIG. 6, for example, ECD used for the EC mirror is formed that ITO layer A, the first electrocromic layer B, a solid electrolyte layer C, the second electrocromic layer AD and ITO layer or A1 layer E are laminated on a transparent substrate such as a glass.
The ITO layer A and ITO layer or A1 layer E also function as a transparent electrode and an opposite electrode having a high reflectivity, respectively. Electric conductive clip electrodes are attached on respective output electrodes of upper and lower electrodes and an outer wiring (harness cord) is connected therethrough.
The bare clip electrode and ECD are physically and chemically weak, and the imperfect contact, the chattering of the mirror surface, the noise from the mirror or the like occurs. A vibration is applied on both clip electrode and harness or on both clip electrode and output electrode, there happens that the clip electrode drops out of the determined attaching position Further there are problems that the discharging is easily caused by water which drops from the harness and contacts the output electrode, a rust occurs on the clip electrode or the uneven coloring is caused by an atmosphere moisture.
Therefore it has been taught that the exposed whole surface of the clip is coated by an insulating coating material such as epoxy resin coating, urethane resin coating or acrylic coating as disclosed by a conventional example 1 of Japanese Utility Model Registration Publication No. Hei 5-22919.
In the EC mirror, it is taught that a rust proof and a water proof effect on the output electrode is achieved to support and cover the mirror end surface by a mirror holder made of a heat shrinkage resin as disclosed by a conventional example 2 of Japanese Utility Model Registration Publication No. Hei 6-16833.
In a conventional example 3 disclosed by Japanese Utility Model Registration Application Publication No. Hei 2-35120, a layer consisting of ECD is cased in a transparent resin made bag and the inside thereof is sealed in a deaeration manner.
In the conventional example 1 of the mirror disclosed by Hei 5-22919, only the clip is covered and protected by an insulating coating and the layer consisting of ECD needs to be sealed by a sealing resin, however, the sufficient water proof for ECD can not be achieved by the sealing resin only. In using the mirror, the coloring layer or the electrode layer of ECD is attacked by water moisture submerging from a short clearance between said resin and the substrate or from the sealing resin surface.
In the conventional example 2 disclosed by Hei 6-18833, there has been a problem of the heat generated from forming the holder attacking ECD and there is further problem in the sealing ability so that a tight sealing of the holder and the mirror body can not be achieved sufficiently. The water submerging is readily caused by a weak sealing ability and the chattering of the mirror surface occurs by a vibration due to a heavy weight of ECD.
In the conventional example 3 of the mirror disclosed by Hei 2-35120, the outer appearance of the mirror is decreased since the mirror is designed that a image is reflected crossing through a cover provided on the mirror and a wiring of the harness is not easily performed.